JP2007027187A - Plasma treatment apparatus and plasma treatment method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma treatment apparatus where a treatment characteristic can be equalized while filament-like electric discharge effective for the improvement of treatment speed is used, and neither increase of apparatus cost nor complication of an apparatus configuration are caused. <P>SOLUTION: The plasma treatment apparatus is provided with an electrode unit formed of a pair of a first electrode and a second electrode mutually adjacent across an insulator, a gas supply means which is confronted of the electrode unit and supplies gas to a space of ordinary pressure connected to an outer unit, a gas discharge means for discharging gas from the space, and a conveyance means which introduces and carries out an object to be treated to the space and carries it out. The electrode unit can generate filament-like electric discharges arranged between the first and second electrodes at almost equal pitches when electric power is supplied so as to form plasma. The electrode unit, the gas supply means, and the gas discharge means are arranged in such a way that a generation position of the filament-like electric discharge continuously moves by a gas flow flowing to the gas discharge means from the gas supply means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a plasma processing apparatus and a plasma processing method using the same, and more particularly to a plasma processing apparatus and a plasma processing method using plasma generated by filament discharge.

  In recent years, atmospheric pressure has been generated in which plasma is generated at atmospheric pressure or in the vicinity thereof and plasma processing such as thin film formation, substrate processing, substrate surface treatment, etc. is performed on various substrates using the chemical reaction by the plasma. Various plasma processing apparatuses have been proposed. If it is possible to perform plasma processing near atmospheric pressure, there is no need to evacuate the reaction vessel to a high vacuum, and the configuration of the apparatus can be simplified, so there is an advantage that the manufacturing cost of the plasma processing apparatus can be greatly reduced. .

  As an atmospheric pressure plasma processing method, a gas flow path is formed between opposing electrodes, a voltage is applied between the electrodes to generate plasma between the electrodes, and an object to be processed is placed between the electrodes. A method for performing a desired process is known (see, for example, Patent Document 1). Here, such an atmospheric pressure plasma processing method is referred to as a direct plasma method.

  In the direct plasma method, active species are generated very close to the surface of the object to be processed, and the generated active species reach the surface of the object to be processed earlier than it is deactivated. is there. On the other hand, the direction of the electric lines of force is substantially perpendicular to the surface of the object to be processed, so that the plasma inevitably comes into direct contact with the surface of the object to be processed. When discharge occurs, there is a problem that the object to be processed is seriously damaged.

  On the other hand, as an atmospheric pressure plasma processing method in which the plasma does not directly contact the object to be processed and a desired processing can be performed, a gas flow path is formed between the opposed electrodes, and a voltage is applied between the electrodes to generate the plasma. A method is known in which active species are generated and ejected toward an object to be processed disposed outside the discharge region (see, for example, Patent Document 2). Here, such an atmospheric pressure plasma processing method is referred to as a remote plasma method.

In the remote plasma method, the plasma generation position is far from the object to be processed, and active species generated in the plasma diffuse and reach the surface of the object to be processed. Has the advantage of not increasing.
However, while having such advantages, the processing speed is slow because there are many active species that are deactivated before reaching the surface of the object to be processed from the plasma generation position. To solve this problem, a plurality of electrodes are arranged. Therefore, the number of generated plasmas has to be increased, and there is a problem that the apparatus cost increases.

  Even if the number of generated plasmas is increased, a gas flow path is formed between the opposed electrodes, so that it is difficult to use the reaction gas once subjected to plasma discharge for plasma discharge again. There is a problem that the utilization efficiency of the reaction gas is lowered and the cost for the reaction gas is increased.

  Therefore, as an atmospheric pressure plasma processing method that realizes processing that has a high processing speed and that does not damage the object to be processed, an electrode unit comprising a pair of power application electrodes and a ground electrode adjacent to each other with an insulator interposed therebetween is provided. The atmospheric pressure is obtained by arranging the object to be processed so as to face the electrode unit, forming a gas flow path between the insulator and the object to be processed, and applying a voltage between the power application electrode and the ground electrode. A method is known in which plasma is generated and treatment is performed using active species generated in the atmospheric pressure plasma (see, for example, Patent Document 3). Here, such an atmospheric pressure plasma processing method is referred to as a semi-remote plasma method.

According to the semi-remote plasma method, the direction of electric lines of force and the surface of the object to be processed are substantially parallel, and the plasma generation position is separated from the object to be processed. Like the plasma method, the damage is less than the direct plasma method. In addition, according to the semi-remote plasma method, discharge occurs in the gas flow path between the insulator and the object to be processed, so that there are few active species to be deactivated, and the processing becomes faster than the remote plasma method.
Furthermore, when the number of plasmas generated by arranging a plurality of electrodes is increased in order to improve the processing speed, the reaction gas supplied to the plasma discharge on the upstream side in the gas flow direction is also converted into the plasma discharge on the downstream side in the gas flow direction. Since it can be used again, the utilization efficiency of the reaction gas becomes very high, and the cost for the reaction gas can be reduced as compared with the remote plasma method. Under such circumstances, research on the semi-remote plasma method is being actively promoted.

Here, how the discharge state of the semi-remote plasma method generally changes with the application of voltage will be described.
If the voltage applied between adjacent electrodes is increased with the reactant gas flowing in the gas flow path, glow discharge occurs when the discharge start voltage is exceeded. In this state, the ionization of the gas molecules caused by the electrons accelerated by the electric field colliding with the gas molecules occurs in the entire discharge space, resulting in a spatially uniform discharge. However, since the electric field in the plasma space is low, ionization proceeds slowly, the density of electrons in the plasma is low, and as a result, the density of active species is also low, resulting in a very slow processing speed.

When the applied voltage is further increased from the state where glow discharge is generated, filamentous discharge with high brightness is generated at an equal pitch. Since the filament discharge region has a higher electron density than the other regions, the active species density is also extremely high, and a high processing speed can be obtained if processing is performed in the filament discharge region (for example, (See Patent Document 4). The atmospheric pressure plasma discharge has a feature that the voltage range from the glow discharge to the filament discharge is small.
Japanese Patent No. 3014111 Japanese Patent No. 2537304 JP 2000-306848 A JP 2000-169977 A

However, plasma processing using filamentary discharge has the following three problems.
First, a processing characteristic distribution reflecting filamentary discharge is generated. As described above, in filamentous discharge, a region having a high electron density is locally generated. Therefore, a portion corresponding to a position immediately below the position where the filamentous discharge is generated in the object to be processed has a high processing speed. The processing speed is low in the portion corresponding to the position immediately below the position where the filament discharge is not generated. As a result, a large variation occurs in the processing effect on the object to be processed.

  Secondly, when a plasma by filament discharge is applied to an object to be processed in which a conductor pattern and a semiconductor or insulator pattern are mixed or laminated, such as a liquid crystal substrate, it is given to the object to be processed. The damage is large. Since the electric field strength locally increases in the filament-shaped discharge portion, electric lines of force may be formed not only between the power application electrode and the ground electrode but also between the power application electrode and the workpiece. Therefore, not only a very large processing characteristic distribution occurs, but in some cases, a large amount of damage is caused to the object to be processed.

  Thirdly, the durability of the electrode unit component is reduced. As described above, since the filament discharge generation position is fixed, when a material with low thermal conductivity is used for the insulator, the temperature of the filament discharge generation position rises locally and insulation is caused by thermal stress. The body may break. The region where the crack is generated is in a plasma state different from the region where the crack is not generated, which causes a processing characteristic distribution. In order to solve this, it is necessary to replace the insulator and increase the maintenance cost of the apparatus.

Because of these problems, when processing using filamentary discharge is performed, processing applications and processing targets are limited, and even when processing is performed, the process window for obtaining necessary processing characteristics becomes very narrow. For this reason, the plasma treatment by filamentary discharge can be used for detoxification treatment of exhaust gas, but it should be avoided especially in the treatment of substrates. Rather, filamentous discharge is suppressed and plasma treatment is performed by glow discharge. There are many current situations.
However, in the case of processing by glow discharge, it is necessary to compensate for the low processing speed by increasing the number of electrode sets, which increases the device cost and complicates the device configuration. In particular, this problem becomes more prominent as the workpiece becomes larger.

  The present invention has been made in consideration of the above-described circumstances, and it is possible to achieve uniform processing characteristics while utilizing filamentary discharge effective for increasing the processing speed, and further increase the cost of the apparatus. The present invention also provides a plasma processing apparatus that does not cause a complicated configuration of the apparatus.

  The present invention relates to an electrode unit composed of a pair of first and second electrodes adjacent to each other with an insulator interposed therebetween, and gas supply means for supplying gas to a normal pressure space facing the electrode unit and communicating with the outside. The gas discharge means for discharging the gas from the space; and the transfer means for introducing, transferring and carrying out the object to be processed into the space, and the electrode unit is interposed between the first and second electrodes when power is turned on. Plasma can be generated by generating filamentary discharges arranged at substantially equal pitches, and the electrode unit, gas supply means, and gas discharge means have continuous filament discharge occurrence positions due to the gas flow flowing from the gas supply means to the gas discharge means. The plasma processing apparatus is provided so as to move to each other.

According to the present invention, the generation positions of filamentary discharges arranged at substantially equal pitches are continuously moved by the gas flow, so that the processing characteristics can be made uniform while increasing the processing speed.
Moreover, since the filament discharge generation position moves continuously, damage to the object to be processed is also suppressed.
Furthermore, since the gas flow is used as means for moving the filament discharge generation position, the apparatus cost is not increased and the apparatus configuration is not complicated.

  The plasma processing apparatus according to the present invention supplies gas to an electrode unit composed of a pair of first and second electrodes adjacent to each other with an insulator interposed therebetween, and a normal pressure space facing the electrode unit and communicating with the outside. Gas supply means; gas discharge means for discharging gas from the space; and transport means for introducing, transporting, and unloading an object to be treated in the space. Plasma can be generated by generating filamentary discharges arranged at approximately the same pitch between two electrodes, and the electrode unit, gas supply means and gas discharge means generate filament discharges by the gas flow flowing from the gas supply means to the gas discharge means. The positions are respectively arranged so as to move continuously.

  In the plasma processing apparatus according to the present invention, the normal pressure means atmospheric pressure or a pressure near atmospheric pressure. Therefore, in the plasma process apparatus according to the present invention, the atmospheric pressure includes not only atmospheric pressure, but also pressure reduced to some extent from atmospheric pressure and pressure pressurized to some extent from atmospheric pressure.

The pair of first and second electrodes constituting the electrode unit is only required to be formed of a conductor, and the material thereof is not particularly limited. Specific examples thereof include conductive materials such as aluminum, copper, and brass. A metal material is mentioned.
The insulator sandwiched between the first and second electrodes is not particularly limited as long as it is formed of an insulating material having excellent heat resistance, voltage resistance, plasma resistance, and gas resistance. However, specific examples include insulating materials such as Al2O3, MgO, TiO2, and AlN.
Note that at least the surface of the first electrode and the second electrode facing the object to be processed is covered with an insulator so that the surface is not affected by the reaction gas, the active species generated in the plasma, the product after the reaction, etc. It is preferred that

The gas supply means is not particularly limited as long as it has a configuration capable of supplying gas to a normal pressure space facing the electrode unit and communicating with the outside, and specific examples thereof include a gas cylinder and a gas cylinder. Examples thereof include a gas supply path leading into the space, and a gas flow rate adjusting mechanism provided in the gas supply path.
The gas discharge means may be any gas discharge means as long as it can discharge gas from the space at normal pressure facing the electrode unit and communicating with the outside, and its configuration is not particularly limited, but as a specific example, for example, an exhaust pump, What is comprised from the gas exhaust path derived | led-out from the said space and connected to the exhaust pump is mentioned.

Any conveying means may be used as long as it can introduce the object to be treated into a normal pressure space facing the electrode unit and communicate with the outside, convey the object to be treated in the space, and unload the object from the space. Well, the configuration is not particularly limited.
As the gas, various gases can be used depending on the purpose of the treatment, and it is not limited, but it is desirable to include a rare gas such as He, Ne, Ar so that the discharge can be easily maintained. An additive gas is added to the rare gas according to a desired treatment. As the additive gas, for example, an oxidizing gas such as O 2, air, or water vapor may be used if processing such as cleaning of the organic substance on the surface of the object to be processed, removal of the resist, or processing of the organic material film is performed. If an etching process of a silicon material such as SiO 2 or SiN is performed, a halogen gas such as CF 4, CHF 3, or SF 6 may be used.

  In the plasma processing apparatus according to the present invention, the gas flow flowing from the gas supply means to the gas discharge means preferably includes a gas flow having a directional component orthogonal to the direction of the electric force line from the first electrode to the second electrode.

  From another point of view, the present invention uses the above-described plasma processing apparatus according to the present invention to supply a gas from the gas supply means to a normal pressure space facing the electrode unit and communicating with the outside. And generating a plasma by generating filamentary discharges arranged at substantially equal pitches between the first and second electrodes, and introducing and transporting the workpiece to the space by the transport means The step of supplying gas from the gas supply means is a step of supplying gas so that the generation position of the filament-like discharge generated by the power supply is continuously moved by the gas flow flowing from the gas supply means to the gas discharge means. The present invention also provides a plasma processing method characterized by the above.

  In the above-described plasma processing method according to the present invention, the step of supplying the gas from the gas supply means is performed such that the gas flow flowing from the gas supply means to the gas discharge means is in the direction of the electric force lines directed from the first electrode to the second electrode. It is preferable that the gas is supplied so as to include a gas flow of orthogonal direction components.

  Further, in the above-described plasma processing method according to the present invention, the step of supplying the gas from the gas supply means includes the direction of the gas flow at the portion facing the electrode unit and the direction of the electric force lines from the first electrode to the second electrode. It may be a step of supplying gas so that the angle θ formed satisfies the condition of 0 <θ <90 °.

  Further, in the above-described plasma processing method according to the present invention, the speed at which the filament discharge generation position continuously moves is the flow velocity of the gas flow in the direction component orthogonal to the direction of the electric force line from the first electrode to the second electrode. And may be approximately equal.

  Further, the gas is supplied so that the angle θ formed by the direction of the gas flow at the portion facing the electrode unit and the direction of the electric force line from the first electrode toward the second electrode satisfies the condition of 0 <θ <90 °. In the above plasma processing method, the flow velocity J of the gas flow flowing from the gas supply means to the gas discharge means is the filament discharge pitch M when the filament discharge generation position does not move, the workpiece moving speed V, The width W of the plasma generation region in the direction parallel to the direction of the electric force line from the first electrode to the second electrode, the angle θ, and an integer k equal to or greater than 1 are set so as to satisfy the relationship of J = kMV / (Wsinθcosθ). May be.

  In the plasma processing method according to the present invention, the object to be processed is a liquid crystal substrate substrate in which a conductor pattern and a semiconductor or insulator pattern are mixed or laminated on a glass substrate, and the gas supplied from the gas supply means is A reactive gas in which an oxidizing gas or a halogen gas is added to a rare gas may be used.

  Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

Embodiments A plasma processing apparatus and a plasma processing method using the same according to an embodiment of the present invention will be described with reference to FIGS.
1 is a transverse sectional view of the plasma processing apparatus according to the embodiment (XX ′ sectional view of FIG. 2), and FIG. 2 is a longitudinal sectional view of the plasma processing apparatus according to the embodiment (YY ′ sectional view of FIG. 1). 3 is a bottom view of the electrode unit of the plasma processing apparatus shown in FIG. 1, and FIG. 4 is an explanatory view for explaining how the filament discharge moves.

As shown in FIGS. 1 to 3, the plasma processing apparatus 18 according to the embodiment includes a pair of high voltage application electrodes (first electrodes) 2 and ground electrodes (second electrodes) 3 that are adjacent to each other with the insulator 4 interposed therebetween. A gas introduction port (gas supply means) 6 for supplying a reactive gas to a gas flow path (normal pressure space) 9 facing the electrode unit 1 and communicating with the outside, and a gas flow from the gas flow path 9 A gas discharge port (gas discharge means) 7 for discharging the gas and a transfer device (transfer means) 8 for introducing the object to be processed 10 into the gas flow path 9 and transferring and discharging it.
The electrode unit 1 can generate plasma 5 by generating filamentary discharges arranged at substantially equal pitches between the high voltage application electrode 2 and the ground electrode 3 when power is supplied from the power source 11. The introduction port 6 and the gas discharge port 7 are respectively arranged such that the filament discharge generation position continuously moves by the gas flow flowing through the gas flow path 9 from the gas introduction port 6 to the gas discharge port 7.

The high voltage application electrode 2 is connected to a power source 11 and the ground electrode 3 is grounded. Since the insulator 4 is sandwiched between the high voltage application electrode 2 and the ground electrode 3, when a voltage is applied between the high voltage application electrode 2 and the ground electrode 3, a part of the insulator 4 The power transmission line open end 12 is formed in the region of. The electric power input from the power supply 11 reaches the power transmission line open end 12 and generates a high electric field in the vicinity of the power transmission line open end 12. When the electric field exceeds the discharge start electric field, plasma 5 is generated near the open end 12 of the power transmission line.
In this embodiment, the high voltage application electrode 2 and the ground electrode 3 are made of Al, and the insulator is made of Al2O3. A high frequency power source of 13.56 MHz is used as the power source 11, but if necessary, a device for controlling the impedance of the resonance circuit including the power source and the plasma in order to efficiently apply power to the high voltage application electrode 2. It may be inserted.

By introducing the reaction gas from the gas introduction port 6 and exhausting from the gas discharge port 7, the reaction gas flows through the gas flow path 9 formed between the electrode unit 1 and the object to be processed.
As the distance L between the electrode unit 1 and the object to be processed 10 is set to be small, the number of active species that reach the object to be processed 10 before being deactivated is increased and the processing speed is improved. If the discharge space is too large, the distance between the discharge space and the object to be processed 10 becomes too short, so that arc discharge occurs between the high voltage application electrode 2 and the object to be processed 10, and the object to be processed 10 may be seriously damaged. Arise. An appropriate value of the distance L between the electrode unit 1 and the workpiece 10 is appropriately changed according to the electric field strength in the discharge space determined by the electrode structure, input power, and the like.

  When the reactive gas is supplied to the generated plasma 5, the reactive gas is excited and active species are generated. Here, the input power is adjusted to generate a filament discharge. It is desirable that the electric power input at this time is as large as possible because the processing speed can be improved. However, if the electric power is excessively large, the discharge space is excessively expanded toward the object to be processed 10. An arc-like discharge may occur between the workpiece 10 and the object 10 to be processed. For this reason, the appropriate value of the input power is the kind of the reaction gas, the composition of the reaction gas, the flow rate of the reaction gas, the distance L between the electrode unit 1 and the object to be processed 10, the high voltage application electrode 2 and the ground electrode 3 It is appropriately determined according to the distance D, required processing capacity, and the like.

  Here, in this embodiment, the angle θ formed by the direction of electric force lines 13 from the high voltage application electrode 2 to the ground electrode 3 and the gas flow direction 14 below the electrode unit 1 is 0 <θ <90. The arrangement of the electrode unit 1, the gas inlet 6 and the gas outlet 7 is set so as to satisfy the condition of °. When filamentous discharge is generated in this state, the filamentous discharge is generated continuously in an oblique direction from the upstream side to the downstream side in the gas flow direction 14, that is, along the direction orthogonal to the electric force line direction 13. Moving.

  While maintaining the state of the plasma 5 as described above, when the workpiece 10 is installed in the transfer device 8 and the workpiece 10 is transferred in a direction parallel to the gas flow direction 14, the activity diffused toward the workpiece 10 is diffused. The seeds act on the workpiece 10 and the plasma treatment proceeds.

Here, focusing on filament discharge, the plasma processing apparatus 18 of the present embodiment is compared with the conventional plasma processing apparatus. FIG. 5 is a longitudinal sectional view of a conventional plasma processing apparatus, and corresponds to FIG. 2 of the plasma processing apparatus of the present embodiment.
As shown in FIG. 5, in the electrode unit 101 of the conventional plasma processing apparatus, the electric force line direction 113 from the power application electrode 102 to the ground electrode 103 and the gas flow direction 114 below the electrode unit 101 are approximately parallel. And the gas flow component in the direction crossing the direction of the electric field lines is almost zero. For this reason, in the conventional plasma processing apparatus, the generation | occurrence | production position of filamentous discharge is fixed without moving, and it arranges at equal pitch.

  On the other hand, in the plasma processing apparatus 18 of the present embodiment shown in FIGS. 1 to 3, an electric force line direction 13 from the high voltage application electrode 2 to the ground electrode 3 and a gas flow direction 14 below the electrode unit 1 are formed. Since the angle θ is set so as to satisfy the condition of 0 <θ <90 °, the gas flow flowing in the direction intersecting the electric force line direction 13 is along the direction orthogonal to the battery force line direction 13. The generation position of the filament discharge moves continuously. As a result, when the plasma 5 is observed from the bottom surface of the electrode unit 1 as shown in FIG. 3, the electric force from the plasma end 15 toward the plasma end 16 is maintained while the filament discharge generation position is maintained at the filament pitch M. It will appear to move along a direction orthogonal to the line direction 13.

  The moving speed of the filament-like discharge generation position increases as the gas flow rate increases, and finally the filament-like discharge is apparently uniform until it becomes impossible to distinguish between the strong emission region and the weak emission region. Is possible. Further, as the value of θ increases, the gas flow of the direction component orthogonal to the electric force line direction 13 increases, so that the moving speed of the filament discharge generation position increases. On the other hand, the higher the gas flow rate, the shorter the time for the reaction gas to stay in the plasma 5 and the lower the decomposition efficiency of the reaction gas, so the processing speed decreases. For this reason, an excessive increase in gas flow rate should be avoided.

Therefore, as a result of intensive studies on the gas flow rate, the present inventors have found that the flow velocity of the gas flow in the direction component orthogonal to the electric force line direction 13 is substantially equal to the moving speed of the filament discharge occurrence position. The gas flow rate (the flow rate of the gas flow flowing from the gas inlet 6 to the gas outlet 7) that is preferable for obtaining the best processing characteristics was considered.
In other words, the inventors of the present invention have described the gas flow rate J, the filament discharge pitch M, the moving speed V of the workpiece, the width W of the plasma generation region, and the electric flux line direction 13 and the gas flow, at which the best processing characteristics can be obtained. The relationship to be satisfied by the angle θ formed with the direction 14 was considered as follows.

First, as shown in FIG. 4, a filamentous discharge generation position A1 having a width W moves in the plasma generation region C to reach the filamentous discharge generation position A2, and at the same time, the element B1 generates plasma in the transport direction 17. Consider a processing step that moves in the region C to reach the element B2.
At this time, a time T1 for the filamentous discharge generation position A1 to reach A2 is expressed by the following formula 1.

T1 = M / (Jsin θ) (Formula 1)

Next, the time T2 until the element B1 reaches B2 is expressed by the following equation 2.

T2 = W / (V / cos θ) (Expression 2)

When T1 = T2, all points in the element A1 pass through the filament-like discharge generation position k times, so that the inside of the element B1 is uniformly processed and reaches B2. That is, the gas flow rate J satisfies the following formula 3. However, k is an integer of 1 or more.

J = kMV / (Wsin θ cos θ) (Equation 3)

In the present embodiment, the uniformity of the processing characteristics can be drastically improved by setting the gas flow rate obtained by Expression 3.

  As described above, the plasma processing by filament discharge of the present embodiment can solve the problems that occur when the plasma processing by conventional filament discharge is performed.

  First, since the position where the filament discharge is generated is moved and made uniform, a region where the electron density is locally increased does not occur, and the processing speed is constant in the processing region of the workpiece 10. Become. For this reason, the dispersion | variation in the processing characteristic of the to-be-processed object 10 is reduced significantly.

  Secondly, the position where the filament discharge is generated moves and the concentration of the local electric field strength is relaxed, so that it is difficult to form electric lines of force between the high voltage application electrode 2 and the workpiece 10. The damage to the object to be processed 10 is reduced. For this reason, it can process without giving damage to the to-be-processed object 10 in which a conductor pattern and a semiconductor or an insulator pattern are mixed or laminated | stacked, such as a liquid crystal substrate.

  Thirdly, since the position where the filamentous discharge is generated moves, the temperature of the insulator 4 does not rise locally and does not break due to thermal stress. Therefore, the durability of the electrode unit 1 does not deteriorate.

As a result of the above, the plasma processing apparatus 18 according to the present embodiment can be used for various plasma treatments that have not been suitable for plasma treatment by filament discharge.
Further, since the plasma processing is performed by filament discharge, the processing speed is remarkably increased as compared with the plasma processing by glow discharge. Therefore, it is not necessary to compensate for the slow processing speed by increasing the number of electrode sets, as in the case of processing by glow discharge.
As described above, according to the plasma processing apparatus 18 of the present embodiment, it is possible to perform plasma processing with high processing speed and uniform processing characteristics without increasing costs and complication of the apparatus configuration.

In the present embodiment, the electrode unit 1 having the structure shown in FIGS. 1 to 3 has been exemplified, but the electrode unit 1 of the plasma processing apparatus 18 according to the present invention is not necessarily in the structure illustrated in the present embodiment. It is not limited.
In the present embodiment, the rectangular gas inlet 6 and the gas outlet 7 are illustrated, but as long as the gas can be uniformly supplied to the discharge space, the gas inlet 6 and the gas outlet 7 are not necessarily rectangular and the shape is not particularly limited. .
In the present embodiment, 13.56 MHz is used as the frequency of the power supply 11, but it is not necessarily limited to this frequency.
In the present embodiment, the case where the transport direction 17 of the workpiece 10 and the gas flow direction 14 are the same has been described, but the transport direction 17 of the workpiece 10 and the gas flow direction 14 may be opposite to each other. Good.

A test example in which a silicon film is etched using the plasma processing apparatus 18 according to the above-described embodiment will be described below.
As the object to be processed 10, a substrate in which a silicon film was formed on a glass substrate was used. The substrate size is 400 mm square. In an atmospheric pressure atmosphere, a reaction gas in which He, CF4, and O2 are mixed at a volume ratio of 100: 5: 2 is introduced from the gas inlet 6 so that the gas flow rate becomes 1.2 m / min. It was discharged from the outlet 7. The distance L between the electrode unit 1 and the workpiece 10 was 4 mm, and the moving speed V of the workpiece 10 was 3.6 m / min.

In this state, the angle θ formed between the electric force line direction 13 from the high voltage application electrode 2 to the ground electrode 3 and the gas flow direction 14 below the electrode unit 1 and the power supplied to the power application electrode 2 were changed. .
First, when 700 W of electric power was applied while the angle θ was 0 °, glow discharge was generated (this state is referred to as “plasma A”). Furthermore, when the input power was increased to 2000 W with the angle θ kept at 0 °, filamentary discharge was generated. At this time, the positions where the filament discharges were generated were arranged at an equal pitch without moving, and the filament pitch M was 1 mm (this state is referred to as “plasma B”). Next, when an electric power of 2000 W was applied with the angle θ set at 45 °, the filament discharge generation position moved (this state is referred to as “plasma C”). In any of the plasmas A to C, the width W of the plasma generation region in the direction parallel to the lines of electric force was 3 mm.

  Next, in a state where each of the plasmas A to C was generated, the object to be processed 10 was conveyed and an etching process was performed. Table 1 below shows the results of evaluating the average etching depth and variations thereof.

As is apparent from Table 1, the processing with plasma A has a small processing characteristic variation but the processing speed is slow, and the processing with plasma B has a high processing speed but a large processing characteristic variation.
On the other hand, it can be seen that the processing using plasma C, which takes advantage of the present embodiment, is excellent in both processing characteristic variation and processing speed.

It is a cross-sectional view (XX 'cross-sectional view of FIG. 2) of the plasma processing apparatus by the Example of this invention. It is a longitudinal cross-sectional view (YY 'cross-sectional view of FIG. 1) of the plasma processing apparatus by the Example of this invention. It is a bottom view of the electrode unit of the plasma processing apparatus shown by FIG. It is explanatory drawing explaining a mode that a filamentous discharge moves in the plasma processing apparatus by the Example of this invention. It is a longitudinal cross-sectional view of the conventional plasma processing apparatus, and is a figure equivalent to FIG. 2 of the plasma processing apparatus by the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electrode unit 2 ... High voltage application electrode 3 ... Ground electrode 4 ... Insulator 5 ... Plasma 6 ... Gas inlet 7 ... Gas outlet 8 ... Conveyance Apparatus 9 ... Gas flow path 10 ... Object to be processed 11 ... Power source 12 ... Power transmission line open end 13 ... Electric field line direction 14 ... Gas flow direction 15, 16 ... Plasma end 17 ... Conveying direction 18 ... Plasma processing equipment

Claims (8)

  An electrode unit composed of a pair of first electrode and second electrode adjacent to each other with an insulator interposed therebetween, a gas supply means for supplying gas to a normal pressure space facing the electrode unit and communicating with the outside, from the space A gas discharge means for discharging gas; and a transfer means for introducing, transferring, and carrying out the object to be processed in the space, and the electrode unit is arranged at a substantially equal pitch between the first and second electrodes when power is turned on. Plasma can be generated by generating aligned filamentary discharges, and the electrode unit, the gas supply means, and the gas discharge means are configured so that the generation position of the filamentous discharge is continuously moved by the gas flow flowing from the gas supply means to the gas discharge means. Each of the plasma processing apparatuses is disposed in each.   2. The plasma according to claim 1, wherein the gas flow flowing from the gas supply means to the gas discharge means includes a gas flow having a directional component orthogonal to a direction of electric lines of force from the first electrode to the second electrode. Processing equipment.   A step of supplying a gas from a gas supply means to a normal pressure space facing the electrode unit and communicating with the outside using the plasma processing apparatus according to claim 1, and supplying electric power to the electrode unit. Supplying gas from the gas supply means, comprising the steps of generating plasma by generating filamentary discharges arranged at substantially equal pitches between the electrodes, and introducing and transferring the object to be processed into the space by the transfer means. The step of performing the plasma treatment is a step of supplying gas so that the generation position of the filament-like discharge generated by the power supply is continuously moved by the gas flow flowing from the gas supply means to the gas discharge means Method.   The step of supplying the gas from the gas supply means is such that the gas flow flowing from the gas supply means to the gas discharge means includes a gas flow of a directional component orthogonal to the direction of the electric force line from the first electrode to the second electrode. The plasma processing method according to claim 3, wherein a gas is supplied to the substrate.   In the step of supplying gas from the gas supply means, the angle θ formed by the direction of the gas flow at the portion facing the electrode unit and the direction of the electric force line from the first electrode to the second electrode is 0 <θ <90 °. The plasma processing method according to claim 3, wherein the plasma processing method is a step of supplying a gas so as to satisfy a condition.   The speed at which the filament discharge generation position continuously moves is substantially equal to the flow velocity of the gas component having a direction component perpendicular to the direction of the electric force line from the first electrode to the second electrode. 6. The plasma processing method according to any one of 5 above.   The flow velocity J of the gas flow flowing from the gas supply means to the gas discharge means is the pitch M of the filament discharge when the filament discharge generation position does not move, the moving speed V of the workpiece, and the first electrode to the second electrode. The width W of the plasma generation region in a direction parallel to the direction of the electric force line to go, the angle θ, and an integer k equal to or greater than 1, are set so as to satisfy a relationship of J = kMV / (Wsinθcosθ). Item 7. The plasma processing method according to Item 5 or 6.   The object to be processed is a liquid crystal substrate substrate in which a conductor pattern and a semiconductor or insulator pattern are mixed or laminated on a glass substrate, and the gas supplied from the gas supply means is added with an oxidizing gas or a halogen gas to a rare gas. The plasma processing method according to claim 3, wherein the plasma processing method is a reactive gas.

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